Here we go again with the invisible ink and the fine print. T-Mobile says it is fixing errors tied to its forced migration of older plans, but you should not wait for the carrier to notice a bad bill for you.
The practical move is simple: check your next statement line by line before autopay quietly turns a temporary billing mistake into your new normal.
T-Mobile plan migration: what changed
Ars Technica reported July 16 that T-Mobile canceled some longtime subscribers’ free-line promotions during a forced move to new rate plans. T-Mobile told Ars the free-line problem was a technical issue affecting a “very small number of customers” and said it was restoring the discounts, backdating them where needed, and reprocessing accounts.
The same report said T-Mobile is also investigating reports that some people were incorrectly billed for Hulu after migration. Ars also reported that some longtime users are seeing price hikes of up to $6 per line as part of the broader move away from retired plans.
That last part matters because even when a carrier fixes one billing error, the new plan can still cost more than the old one. T-Mobile’s current public plan page says its Experience plans include a five-year price guarantee on talk, text, and 5G data, with exclusions such as taxes and fees.
1. Check every free line and promo credit
If you had a free line, bill credit, loyalty promo, or old account-level discount, treat it as a separate item to verify. Do not just compare the headline plan name.
What to do: open your pre-migration bill and your post-migration bill side by side. Circle every line that used to show as free or discounted. If it disappeared, screenshot both bills before contacting support.
2. Watch for add-ons you did not request
Billing migrations can expose mystery add-ons, duplicate perks, or entertainment charges that were supposed to be included. T-Mobile specifically told Ars it was investigating Hulu billing reports after migration.
What to do: scan the add-ons section first. If an entertainment, hotspot, protection, or international feature appeared without your approval, dispute it immediately and ask for the credit in writing.
3. Do the per-line math, not the account-name math
A new plan name can sound close to your old one while the total bill changes line by line. A $6 per-line increase is $24 a month on four lines before taxes, fees, device payments, or lost discounts.
What to do: divide the new monthly total by the number of paid lines, then compare that with MVNO options on the same network. If the new T-Mobile total no longer earns its premium, you have leverage.
4. Confirm what the new guarantee does not cover
A price guarantee can still leave room for taxes, fees, device charges, perks, insurance, or account extras to change. T-Mobile’s public plan page says the five-year guarantee is for talk, text, and 5G data, and that exclusions like taxes and fees apply.
What to do: separate the base service charge from everything else. If a rep says your price is guaranteed, ask which exact rows on your bill are covered.
5. Escalate before autopay runs
Do not let a disputed migration bill sit until the due date. Once autopay pulls the money, you are asking for a refund instead of stopping an overcharge.
What to do: contact support with bill screenshots, request a case number, and ask the rep to name the missing promo or incorrect charge. If the answer is vague, escalate to retention before the payment date.
The SaveOnPhone read
- Free lines need a line-by-line audit: T-Mobile says affected free-line discounts remain free, but customers still need to confirm the credit actually appears.
- Promos are not the same as plan price: a migration can preserve one benefit while changing another part of the bill.
- Per-line increases add up fast: $6 per line is not small on a family account.
- Use the same-network comparison: if T-Mobile’s retail plan no longer justifies the total, compare lower-cost T-Mobile-network MVNOs before accepting the new bill.
What to do this week
- Download your last bill before migration and your first bill after migration.
- Verify free lines, loyalty credits, and perk credits one by one.
- Look for new add-ons, especially entertainment or hotspot charges.
- Calculate the new per-line total after taxes, fees, and device payments.
- Contact support before autopay if any credit or charge is wrong.